private void btnFile1_Click(object sender, EventArgs e)

        {

            if (openFileDialog1.ShowDialog() == DialogResult.OK)

            {

                txtFile1.Text = openFileDialog1.FileName;

            }

        }

        private void btnFile2_Click(object sender, EventArgs e)

        {

            if (openFileDialog1.ShowDialog() == DialogResult.OK)

            {

                txtFile2.Text = openFileDialog1.FileName;

            }

        }

        private void btnCompare_Click(object sender, EventArgs e)

        {

            if ((txtFile1.Text != "") & (txtFile2.Text != ""))

            {

                try

                {

                    txtMd51.Text = cMd5.GetMD5Hash(txtFile1.Text);

                    txtMd52.Text = cMd5.GetMD5Hash(txtFile2.Text);

                    if (txtMd51.Text == txtMd52.Text)

                    {

                        txtResult.Text = "برابر";

                        txtResult.BackColor = System.Drawing.Color.FromArgb(102,255,204);

                    }

                    else

                    {

                        txtResult.Text = "نابرابر";

                        txtResult.BackColor = System.Drawing.Color.FromArgb(255, 102, 153);

                    }

                }

                catch

                {

                    MessageBox.Show("ورودی نامعتبر", "خطا یک", MessageBoxButtons.OK, MessageBoxIcon.Error);

                }

            }

            else

            {

                MessageBox.Show("ورودی تهی", "خطای دو", MessageBoxButtons.OK, MessageBoxIcon.Error);

            }

        }

        public static string GetMD5Hash(string pathName) // کد آقای تصدیقی

        {

            string strResult = "";

            string strHashData = "";

            byte[] arrbytHashValue;

            System.IO.FileStream oFileStream = null;

            System.Security.Cryptography.MD5CryptoServiceProvider oMD5Hasher =

                       new System.Security.Cryptography.MD5CryptoServiceProvider();

            try

            {

                oFileStream = GetFileStream(pathName);

                arrbytHashValue = oMD5Hasher.ComputeHash(oFileStream);

                oFileStream.Close();

                strHashData = System.BitConverter.ToString(arrbytHashValue);

                strHashData = strHashData.Replace("-", "");

                strResult = strHashData;

            }

            catch (System.Exception ex)

            {

                System.Windows.Forms.MessageBox.Show(ex.Message, "Error!",

                           System.Windows.Forms.MessageBoxButtons.OK,

                           System.Windows.Forms.MessageBoxIcon.Error,

                           System.Windows.Forms.MessageBoxDefaultButton.Button1);

            }

            return (strResult);

        }